Chemistry. Combined Science. Paper 2. Checklists and Knowledge Organisers

Transcription

1 Combined Science Chemistry Paper 2 Checklists and Knowledge Organisers Included in this booklet are the Personalised Learning Checklists (PLC s) for the biology topics included in paper 2. As you work through the topic and revise it at a later date, RAG rate your understanding of each statement to help you focus your revision. The knowledge organisers will support you in addressing these areas.

2 The following table lists the command words used in the external assessments. Command word Add/Label Requires the addition or labelling to a stimulus material given in the question, for example labelling a diagram or adding units to a table. Give careful consideration to all the factors or events that apply and identify which are the most important or relevant. Make a judgement on the importance of something, and come to a conclusion where needed. Obtain a numerical answer, showing relevant working. If the answer has a unit, this must be included. This can include using an equation to calculate a numerical answer. Requires the synthesis of a number of variables from data/information to form a judgement. Looking for the similarities or differences of two (or more) things. Should not require the drawing of a conclusion. Answer must relate to both (or all) things mentioned in the question. Looking for the similarities and differences of two (or more) things. Should not require the drawing of a conclusion. Answer must relate to both (or all) things mentioned in the question. Assess Calculate Comment on Compare Compare and contrast Complete Deduce Describe Determine Devise Discuss The answer must include at least one similarity and one difference. Requires the completion of a table/diagram. Draw/reach conclusion(s) from the information provided. To give an account of something. Statements in the response need to be developed as they are often linked but do not need to include a justification or reason. The answer must have an element which is quantitative from the stimulus provided, or must show how the answer can be reached quantitatively. To gain maximum marks there must be a quantitative element to the answer. Plan or invent a procedure from existing principles/ideas. Identify the issue/situation/problem/argument that is being assessed within the question. Explore all aspects of an issue/situation/problem/ argument. Draw Estimate Evaluate 14 Investigate the issue/situation etc. by reasoning or argument. Produce a diagram either using a ruler or using freehand. Find an approximate value, number, or quantity from a diagram/given data or through a calculation. Review information (e.g. data, methods) then bring it together to form a conclusion, drawing on evidence including strengths, weaknesses, alternative actions, relevant data or information. Come to a supported judgement of a subject s qualities and relation to its context. Command word Explain An explanation requires a justification/exemplification of a point. Give/State/Name Give a reason/reasons Identify Justify Measure Plot Predict Show that Sketch State and explain State what is meant by Write The answer must contain some element of reasoning/ justification, this can include mathematical explanations. All of these command words are really synonyms. They generally all require recall of one or more pieces of information. When a statement has been made and the requirement is only to give the reasons why. Usually requires some key information to be selected from a given stimulus/resource. Give evidence to support (either the statement given in the question or an earlier answer). To determine the dimensions or angle from a diagram using an instrument such as a ruler or protractor. Produce a graph by marking points accurately on a grid from data that is provided and then drawing a line of best fit through these points. A suitable scale and appropriately labelled axes must be included if these are not provided in the question. Give an expected result. Verify the statement given in the question. Produce a freehand drawing. For a graph this would need a line and labelled axis with important features indicated, the axis are not scaled. Make a point and link ideas to justify that point. An explanation requires a justification/exemplification of a point. The answer must contain some element of reasoning/justification, this can include mathematical explanations. When the meaning of a term is expected but there are different ways of how these can be described. When the questions ask for an equation. Occasionally we will ask candidates for a suggestion, for example when asking them to apply their knowledge to a novel situation, but the word suggest is not the command word. The command word follows the word suggest. In our analysis of our current papers, we have noticed that candidates struggle to interpret what is being asked in a suggest question, so we add a word which gives more clarity over what is required, e.g. suggest an explanation. Verbs preceding a command word Suggest a Always used with another command word, e.g. Suggest an explanation. 15

3 Combined Science Paper 2 Checklists Chemistry 5- CC13-15: Groups in the PT, Rates of Reaction Topic Student Checklist R A G Topic 6 Groups in the periodic table Explain why some elements can be classified as alkali metals, halogens or noble gases, based on their position in the periodic table Recall the physical properties of alkali metals Describe the reactions of lithium, sodium and potassium with water Describe the pattern in reactivity of the alkali metals, lithium, sodium and potassium, with water; and use this pattern to predict the reactivity of other alkali metals Explain this pattern in reactivity in terms of electronic configurations Recall the colours and physical states of chlorine, bromine and iodine at room temperature Describe the pattern in the physical properties of the halogens, chlorine, bromine and iodine, and use this pattern to predict the physical properties of other halogens Describe the chemical test for chlorine Describe the reactions of the halogens, chlorine, bromine and iodine, with metals to form metal halides, and use this pattern to predict the reactions of other halogens Recall that the halogens, chlorine, bromine and iodine, form hydrogen halides which dissolve in water to form acidic solutions, and use this pattern to predict the reactions of other halogens Describe the relative reactivity of the halogens chlorine, bromine and iodine, as shown by their displacement reactions with halide ions and use this to predict the reactions of astatine HT ONLY: Explain why these displacement reactions are redox reactions in terms of gain and loss of electrons, identifying which of these are oxidised and which are reduced Explain the relative reactivity of the halogens in terms of electronic configurations Explain why the noble gases are chemically inert, compared with the other elements, in terms of their electronic configurations Explain how the uses of noble gases depend on their inertness, low density and/or non-flammability Describe the pattern in the physical properties of some noble gases and use this pattern to predict the physical properties of other noble gases

4 Chemistry 6 - CC16-17: Fuels Topic Student Checklist R A G Topic 8 Fuels and Earth science Recall what a hydrocarbon is Describe and explain what crude oil is and why it is important Describe and explain the separation of crude oil into simpler, more useful mixtures by the process of fractional distillation Recall the names and uses of the following fractions: gases, petrol, kerosene, diesel oil, fuel oil and bitumen Explain how hydrocarbons in different fractions differ from each other in terms of boiling point, number of C & H's, flammability and viscosity Explain what a homologous series of hydrocarbon compounds is Describe the complete combustion of hydrocarbon fuels including energy changes and products Explain why the incomplete combustion of hydrocarbons can produce carbon and carbon monoxide Explain how carbon monoxide behaves as a toxic gas Describe the problems caused by incomplete combustion in appliances that use carbon compounds as fuels Explain how impurities in some hydrocarbon fuels result in the production of sulfur dioxide Explain some problems associated with acid rain Explain why, when fuels are burned in engines, oxides of nitrogen are formed and that they are pollutants Evaluate the advantages and disadvantages of using hydrogen, rather than petrol, as a fuel in cars Recall the names and sources of some renewable fossil fuels Explain what cracking is and why it is necessary Recall that the gases produced by volcanic activity formed the Earth s early atmosphere Describe what the Earth s early atmosphere was thought to contain Explain what the oceans were formed from Explain why the amount of carbon dioxide in the atmosphere decreases when the oceans were formed Explain how the growth of primitive plants changes the composition of gases in the atmosphere Describe the chemical test for oxygen Describe and explain the greenhouse effect and name the gases that contribute to it Evaluate the evidence for human activity causing climate change Describe the potential effects on the climate of increased levels of carbon dioxide and methane generated by human activity Describe how effects on the climate may be mitigated: consider scale, risk and environmental implications

5 CC3-4 Atoms and the Periodic Table If an atom was the size of a football stadium, the nucleus would only be the size of a small marble sat at the centre. But a marble made of nuclear matter would have a mass the same as A r atom atomic number chemical property electron electron shell electronic configuration element group inert isotopes mass number mean Symbol for relative atomic mass (RAM). Atoms are small particles from which all substances are made. They are the smallest neutral part of an element that can take part in chemical reactions. The number of protons in the nucleus of an atom (symbol Z). Also known as the proton number. How a substance reacts with other substances. Tiny particle with a negative charge that is found in shells around the nucleus of an atom. Area around a nucleus that can be occupied by electrons, usually drawn as a circle (in target diagrams ). Also called an electron energy level or an orbit. The arrangement of electrons in shells around the nucleus of an atom. A simple substance made up of only one type of atom. A vertical column of elements in the periodic table. Elements in the same group generally have similar properties. Does not react. Atoms of an element with the same number of protons (atomic number) but different mass numbers due to different numbers of neutrons. The total number of protons and neutrons in the nucleus of an atom (symbol A). Also known as the nucleon number. An average calculated by adding up the values of a set of measurements and dividing by the number of measurements in the set. neutron nuclear fission nucleus period Electrically neutral subatomic particle found in the nucleus of most atoms. The reaction in which the nucleus of a large atom, such as uranium, splits into two smaller nuclei. The positively charged centre of an atom. A horizontal row in the periodic table. periodic table An ordered list of all known elements. physical property prediction proton relative atomic mass (RAM) relative atomic mass, A r relative charge relative mass subatomic particles X-ray A description of how a material behaves and responds to forces and energy. Hardness is a physical property. What you think will happen in an experiment and why you think this. A positively charge subatomic particle in the nucleus of all atoms. The mean mass of an atom relative to the mass of an atom of carbon-12, which is assigned a mass of 12. The RAM of an element is the mean relative mass of the isotopes in the element. The mean mass of an atom relative to the mass of one-twelfth of an atom of carbon-12, which is assigned a mass of 12. The A r of an element is the mean relative mass of the isotopes in the element. The electric charge of a subatomic particle compared to the charge on a proton. The mass of a subatomic particle compared to the mass of a proton. The smaller particles that make up atoms protons, neutrons and electrons. Electromagnetic radiation that has a shorter wavelength than UV but longer than gamma rays.

6 Word Meaning CC4 a-c Periodic Table, atomic number and electronic configuration Who is Mendeleev and how did he arrange elements into a periodic table? What is an element s atomic number? How do you work out and show the electronic configuration of an element? A 313km diameter crater on the far side of the Moon was named in honour of Mendeleev by the Russian scientists in charge of the Luna 3 space probe. The probe, launched in 1959, was the first to photograph the far side of the Moon. Element 101 is also named after Mendeleev. atomic number chemical property electron electron shell electronic configuration group inert period periodic table physical property prediction relative atomic mass, A r X-ray The number of protons in the nucleus of an atom (symbol Z). Also known as the proton number. How a substance reacts with other substances. Tiny particle with a negative charge that is found in shells around the nucleus of an atom. Areas around a nucleus that can be occupied by electrons, usually drawn as circles. Also called an electron energy level. The arrangement of electrons in shells around the nucleus of an atom. A vertical column of elements in the periodic table. Elements in the same group generally have similar properties. Does not react. A horizontal row in the periodic table. An ordered list of all known elements. A description of how a material behaves and responds to forces and energy. Hardness is a physical property. What you think will happen in an experiment and why you think this. The mean mass of an atom relative to the mass of one -twelfth of an atom of carbon-12, which is assigned a mass of 12. The A r of an element is the mean relative mass of the isotopes in the element. Electromagnetic radiation that has a shorter wavelength than UV but longer than gamma rays.

7 Alkali metals A group of very reactive metals found in group 1 of the periodic table. Bleach To take the colour out of something. Diatomic Two atoms chemically bonded together. Disinfectant Something that destroys or neutralises diseasecarrying microorganisms. Displacement When a more reactive element displaces a less reaction reactive element from one of its compounds. Group A vertical column of elements in the periodic (chemistry) table. Elements in the same group generally have similar properties. Halide A compound formed between a halogen and another element such as a metal or hydrogen. Halogen An element in group 7 of the periodic table. Inert Does not react. CC13 Groups in the periodic table What the main properties of elements in different groups are. What the trends in properties are in different groups. How displacement reactions can be used to show the reactivity of the halogens. Why the noble gases are unreactive. Reactivity of elements as you descend group Alkali metals: Reactivity increases. Halogens: Reactivity decreases. Noble gas Oxidation Oxidised Periodic table Reactivity Redox Reduced Reduction Salt Scientists believe that there is only between 20g and 30g of francium on Earth at any time. The name halogen comes from the Greek words hals (meaning salt ) and gen (meaning to make ) An unreactive gas in group 0 of the periodic table. A reaction in which oxygen is added to a substance loss of electrons by an atom or negative ion. When a substance has gained oxygen (or lost electrons) in a reaction. The chart in which the elements are arranged in order of increasing atomic number. A description of how quickly or vigorously something reacts. A reaction in which both oxidation and reduction occur. When a substance has lost oxygen (or gained electrons) in a reaction. A reaction in which oxygen is removed from a substance; gain of electrons by an atom or positive ion. A compound formed by neutralisation of an acid by a base.

8 CC14-15 Rates of reaction & energy changes in reactions How we can investigate reaction rates. Why changes in temperature, concentration, pressure, and surface area affect reaction rates. What we mean by exothermic and endothermic reactions. How to calculate energy changes in reactions. Japanese scientists have developed a camera to observe very fast reactions; it records 4.4 trillion frames per second. Photosynthesis is an endothermic reaction. Activation energy Active site Bond energy Catalyst Covalent bond Denatured Displacement reaction Endothermic Enzyme Exothermic The minimum amount of energy needed to start a reaction. The space in an enzyme where the substrate fits during an enzyme-catalysed reaction. Energy needed to break one mole of a specified covalent bond. A substance that increases the rate of a reaction without itself being used up. A bond formed when a pair of electrons is shared between two atoms. An enzyme in which the shape of the active site has changed so much that its substrate no longer fits and the reaction can no longer happen. A reaction where a more reactive element takes the place of a less reactive element in a compound. A reaction in which energy is transferred to the reactants from the surroundings. The temperature of the surroundings decreases. A protein produced by living organisms that acts as a catalyst to increase the rate of a reaction. A reaction in which energy is transferred from the reactants to the surroundings. The temperature of the surroundings increases. Mole Neutralisation Precipitation Product Protein Rate Reactant Reaction profile Substrate Variable A mole of something is particles of it. The mass of a mole of a substance is the relative formula mass expressed in grams. A reaction in which an acid reacts with an alkali or a base to produce a salt and water only. A reaction in which an insoluble product is formed from soluble reactants. A substance formed in a reaction. A polymer made up of amino acids. How quickly something happens. A substance used up in a chemical reaction. A diagram to show how the energy stored in substances changes during a chemical reaction. A substance that is changed during a reaction. A factor that can change.

9 CC16 Fuels What we mean by hydrocarbons How crude oil is separated Why crude oil is so useful The differences between complete and incomplete combustion Why cracking is needed The world uses about 96 million barrels of oil each day about 180,000 litres per second. After hydrogen, carbon monoxide is the second most common molecule in interstellar space. Acid rain Alkane Alkene Carbon monoxide Catalyst Combustion Complete combustion Condense Cracking Crude oil Evaporate Feedstock Finite resource Fossil fuel Fraction Rainwater that is more acidic than usual due to air pollution, usually caused by sulfur dioxide and nitrogen oxides. A hydrocarbon in which all the bonds between the carbon atoms are single bon ds. A hydrocarbon in which there are one or more double bonds between carbon atom s. A poisonous gas produced from carbon burning without enough oxygen. A substance that speeds up the rate of a reaction without itself being used up. A chemical reaction in which a compound reacts with oxygen. Combustion of hydrocarbons with enough oxygen present to convert all the fuel into carbon dioxide and water. When a gas turns into a liquid. A chemical react on in which large alkane molecules are split into two or more smaller alkanes and alkenes. A fossil fuel, in the liquid state, formed from the remains of microscopic dead plants and animals that lived in the sea. When a liquid turns in to a g as. Raw material, a substance used to make other substances. Something useful that is no longer made or which is being made very slowly. A fuel formed from the dead remains of organisms over millions of years (e.g. co al, oil or natural gas). A component of a mixture that has been separated by fractional distillation. Complete combustion of hydrocarbons:

10 CC16 Fuels - continued Fractional distillation Fractionating column General formula Greenhouse gas Haemoglobin Homologous series A method of separating a mixture of liquids with different boiling points into individual components (fractions). Tower in which fractional distillation takes place. A type of formula that represents the composition of any member of an homologous series. A gas that helps to trap heat in the atmosphere. Carbon dioxide, methane an d water vapour are greenhouse gases. The red, iron-containing pigment found in red blood cells. A family of compounds with similar chemical properties and gradual variation in physical properties. They have the same general formula, with successive members differing in their molecular formulae by CH 2. Petrochemical Pollutant Red blood cell Saturated Soot Structural formula Substance made from crude oil. A substance that harms living organisms when released into the environment. A biconcave disc containing haemoglobin that gives blood its red colour and carries oxygen around the body to the tissues. Also known as an erythrocyte. A molecule that contains only single bonds between the carbon atoms in a chain. A form of carbon, which is produced as very fine particles when hydrocarbon fuels undergo incomplete combustion. A diagram showing information about the positions of the atoms in a molecule and the bonds between them. Hydrocarbon A compound containing hydrogen and carbon only. Toxic Poisonous. Ignite Impurity Incomplete combustion Molecular formula Natural gas Non-renewable Oxidation Oxide of nitrogen To start burning. Unwanted substance found mixed into a useful substance. When a substance reacts only partially with oxygen, such as when carbon burns i n air producing carbon monoxide and soot (unburnt carbon). Chemical formula that shows the actual number of atoms of each element in a u nit of a substance. A fossil fuel, in the gas state, formed from the remains of microscopic dead plants and animals that lived in the sea. Something that is being used up faster than it is being formed, so it will run out one day if we keep using it. A reaction in which oxygen i s added to a substance; loss of electrons by an atom or negative ion. Any one of a variety of gaseous compounds consisting of only nitrogen and oxygen atoms. Together they are often represented as NO x. Unsaturated Viscosity Weathering A molecule that contains one or more double bonds between carbon atoms in a chain. How thick or runny a liquid is. Low viscosity is very runny, high viscosity is thick. When rocks are broken up by physical, chemical or biological processes.

11 CC17 Earth and Atmospheric Science How scientists explain the formation of the oceans How primitive organisms changed carbon dioxide and oxygen levels What the link is between fossil fuel combustion and climate change The problems climate change may cause The largest volcano in the Solar System is on Mars. It s called Olympus Mons and is 27 km high (3 x the height of Mount Everest). Sea levels have been rising at a rate of over 3 mm per year since Absorb Atmosphere Causal link Climate change Composition Correlation Emit Global warming Greenhouse effect Greenhouse gas Hypothesis Infrared Photosynthesis Resolution Volcanic activity To soak up or take in. The layer of gases that surrounds the Earth. A relationship between two variables, where scientists can show that a change in one variable makes a change occur in the other. For example, burning more fossil fuels (change in first variable) increases the amount of carbon dioxide in the atmosphere (change in another variable, caused by the first). Changes that happen to the glob al weather patterns as a result of global warming. The combination of parts that ad d up to make something. For example, the composition of today s atmosphere is 78% nitrogen, 21% oxygen, 1% argon and other gases. A relationship between two variables, so that if one variable changes so does the other. This can be positive or negative. To give out. The rise in mean surface temperatures on the Earth, thought to be due to increasing a mounts of greenhouse gases such as carbo dioxide. The trapping of warmth by greenhouse gases in the Earth s atmosphere due to radiation from the atmosphere warming the surface of the planet. A gas that helps to trap heat in the atmosphere. Carbon dioxide, methane and water vapour are greenhouse gases. A scientific explanation that is thought up and suggested to explain something. It is used to make predictions that can be tested scientifically. Electromagnetic radiation that we can feel as heat. A series of enzyme-catalysed reactions carried out in the green parts of plants. Carbon dioxide and water combine to form glucose. This process requires energy transferred by light. The smallest change that can be measured by an instrument. For example, in a thermometer it is the smallest temperature change that can be measured. The release of gases and/or molten rock by volcanoes.